Steam-superheater.



E. H. WELLS.

STEAM SUPERHEATER.

APPLICATION FILED AUG.I2. 1913.

Patented Aug. 17, 1915.

2 SHEETS-SHEET 2.

@ El L 'i EDWARD H. WELLS, OF MONTCLAIR, NEW

JERSEY, ASSIGNOR TO THE BABCOCK @t WILCOX COMPANY, 0F BAYONNE, NEW JERSEY, A CORPORATION 0F NEW JERSEY.

STEAM-SUPERHEATER.

Specification of Letters Patent.

Application led August 12, 1913. Serial No. 784,301.

T0 all whom #may concern Be it known that I, EDWARD H. IVELLS, a citizen of the United States, residing at Montclair, in the county of Essex Iand State of New Jersey, have invented certain new and useful Improvements in Steam-Superheaters, of which the following is a specification.

My invention relates to steam superheaters intended for use more particularly in connection with steam boilers, the object of the invention being to provide a construction wherein the cores in the superheater loops shall be held firmly in place but allowing for their easy removal if it is necessary or desired to remove them.

The invention will be understood by reference to the accompanying drawings 1n which- Figure l is a central vertical section through one side of a superheater loop, and the cross box into which it is expended; Fig. 2 a. view similar to Fig. 1 ona larger scale and broken away; Fig. 3 a perspective view of a part of the cross box with the superheater loop in cross section; Fig. 4. a transverse section on the plane of the line 4-4 of Fig. 2; Fig. 5 a transverse section on the plane of the line 5 5 of Fig. 2; Fig. 6 a vertical section showing the lower end of a modification of the core; Fig. 7 a side view of the lower end of the core of Fig. 6; and Fig. 8 a transverse section on the plane of the line 8-8 of Fig. 6.

Similar reference numerals indicate similar parts in the different views.

The use of cores in superheaters is old, the purpose in using them being to evenly distribute the steam between the different loops of the superheater. In many superheaters the combined cross sectional area of the tubes leading from the boxes is four or five times, or even more than that of the cross sectional area of the boxes, and if cores are not used some of the superheater tubes will carry more steam than others, with the result that the tubes carrying the least amount of steam may become over-heated and burned. Again, the amount of heat imparted to the steam, and the superheat obtained will be less with an uneven distribution of steam than it will where the steam is evenly distributed throughout the tubesl Also the presence of the cores leads to an increase in the heat transfer rate as the steam must f'low in a relatively thin film between the cores and the tubes. whereas without cores the steam is distributed over the entire cross sectional area of the tubes and the action is not as effective as where it is made to flow in a thin film.

Referring to Figs. l, 2. 5 the numeral l designates one side of a super-heater loop. the superheater tubes being U-shaped and their ends expanded into cross boxes Q. According to the present invention, the core 3 is of general cylindrical shape, and is. except for the shaping of the core for the purpose herein described, slightly less in diameter than the internal diameter of the tube. The general form is altered in the following manner. The superheater tube is formed with a groove l on its inner surface at any convenient point in its length, and preferably near its lower end. This groove is adapted to be engaged by a projection 5 formed by expanding the core by a suitable tool. The core has sufficient elasticity so that when it is forced into the superheater tube thel projection 5 will spring into groove 4 and the' core will thereby be firmly held in place. To hold the core centrally in the tube any convenient means may be adopted. one method being to expand the core at intel'- vals to provide sections 6 of general oval form shown in Fig. l, the major axes of these sections being equal to the internal diameter of the tube so that the core, at these points. will bear against the inner wall of the tube. As shown in Figs. 2 and 4 these oval sections are distributed along the length of the core and are disposed, some in one di rection and others in a diametrically opposite direction. It is not essential, however, that they be so symmetrically disposed, the essential condition being that the core shall be expanded at intervals to provide proiections which shall bear against the inner wall of the tube. The core is closed at its upper end by a plug 7 held in place b v forming the metal of the core around its circumference.

In practice it has been found that the construction above described will hold the core firmly in place and will properly center it within the tube. If it is desired to remove the core a key is passed, through the hand-hole openings 8, into the lower part of the core and given a half turn after which the core may be pulled out by means of a lever device attached to the key.

The lower end of the core is well inside of the end of the superheater tube when it is located in position. The purpose of this is to prevent interference with the expansion of the tube into the cross box 2. This is a distinct advantage, resulting from the invention, Where superheaters are shipped knocked down and the loops are expanded into the cross boxes in the field. In such cases the cores are placed in position in the superheater loops before shipment and there is less work to do in the field, in addition to making a more compact arrangement for shipment.

In superheater practice it is highly important that there shall be no small pieces inside ofthe superheater which may become detached and be picked up and carried along with the steam into the piping and valves, or possibly to the steam turbine or engine. By constructing the cores as above described there are no small pieces to become detached and any possible trouble of the sort is therefore eliminated.

In Figs. 6 to 8 I have shown a solid core 9 having its lower end 10 drawn -down and made thinner and more flexible than the body and formed, substantially as shown, with an elbow 11 adapted to spring into the groove 4 formed on the inner surface of the tube l. 'The core 9 is expanded at intervals so as to provide sections l2 of general oval form to hold the core centrally in the tube, the major axes of said sections beingjequal to the internal diameter of the tube.

The end 13 of arm 10 is preferably bent into the form of a hook, or it may be upset to form a knob or head, so that it may be grasped by a suitable tool for removing the core.

What I claim and desire to secure by Letters Patent of the United States is z- 1. A superheater tube having an indentation or recess in its inner wall, and a core having a projection adapted to engage said indentation or recess to retain the core in position in the tube, for the purpose described.

2. A steam superheater tube of substantially uniform diameter throughout its length and having an indentation or recess in itsainner Wall, and a core of less diameter than the tube, said core having a projection seated in said recessl to retain the core in position in the tube for the purpose described.

3. A superheater tube having an indentation or recess in its inner Wall, a core having a projection seated in said indentation or recess, and means for holding said core centrally within the tube for the purpose described.

4. A superheater tube having an indentation or recess in its inner wall, and a core having a projection seated in said indentation or recess to retain the core in position in the tube, said core also having flattened sections to bear against the inner wall of the tube, for the purpose described.

5. A superheater tube having an identation or recess in its inner Wall, and a core having a projection seated in said indentation or recess, said core also being flattened at intervals to provide sections of general oval form to bear against the inner wall of the tube, for the purpose described.

6. A superheater tube having an indentation or recess on its inner Wall, and a core of less diameter than the tube and having an expanded projection seated in said vindentation or recess to lock the core in the tube against longitudinal movement.

7. A superheater tube having an indentation or recess on its inner wall, and a core of less diameter than the tube and having an expanded projection seated in said indentation or recess to lock the core in the tube against longitudinal movement, said core also having expanded sections to provide projections to bear against the inner Wall of the tube to lock the core against lateral movement.

8. A superheater tube having anindentation or recess in its inner wall, and a core having a projection seated in said indentation or recess, said core being closed at its upper end, for the purpose described.

9. A superheater tube having an indentation or recess in its inner wall, and a hollow core of less diameter than the tube, said core having a flattened section forming a projection seated in said indentation or recess to lock the core in the tube against longitudinal movement.

10. A superheater tube having an indentation or recess in its inner wall, a hollow core of less diameter than the tube, said core having a flattened section forming a projection seated in saidindentation or recess to lock the core in the tubeagainst longitudinal movement, and means for holding said core centrally within the tube.

11. A superheater tube having an indentation or recess in its inner wall, and a corehaving a projection seated in said indentation or recess, and also flattened at intervals to provide sections of general oval form to bear against the inner Wall of the tube.

In testimony whereof I have ,hereunto signed my name in the presence of two subscribing witnesses.

EDWARD H. WELLS.

Witnesses:

D. S. JA'coBUs, WM. SHELDRICK.

copies of this patent may be obtained for ve cents each, by addressing the "Commissioner of Patenta, Washington, D. C. 

